1. Field of the Invention
The present invention relates to a trigger operated dispensing device for mounting to the top neck of a storage container. Although such devices, known as trigger sprayers, can be reused, often times they are disposed of. To facilitate disposal and/or recycling of the sprayer, the present invention relates to a non metallic all synthetic or all plastic trigger sprayer.
2. Description of the Related Art Including Information Disclosed Under 37 CFR .sctn. 1.97-1.99.
Heretofore, various trigger sprayers have been proposed.
A common construction for a trigger sprayer includes a body, a chamber or cylinder in the body, a piston and a metal spring in the cylinder and inlet and outlet valves, one of which is typically a metal ball valve . The spring biases the piston out of the cylinder, and a trigger is pivotally connected to the body and to the piston for urging the piston into the cylinder during a pumping stroke.
Other types of trigger operated sprayers also have been proposed and three examples of same are disclosed in the following three patents:
______________________________________ U.S. Pat. No. Patentee ______________________________________ 4,915,263 Corba 4,352,443 Libit 4,241,853 Pauls et al. 3,986,644 Grogan et al ______________________________________
In the Corba U.S. Pat. No. 4,915,263 a trigger sprayer having a plastic frame, including a trigger, an upper leg, a flexure, a lower leg, and a cap, together with a pumping device, a nozzle assembly and a delivery arm is disclosed. The pumping device is mounted in the cap of the frame and a tubular extension of the pumping device is inserted through an opening of the cap to be press-fitted to the delivery arm to create a connection between the container and the nozzle assembly mounted at the delivery arm.
The pumping device of the sprayer is made mainly out of plastic, but includes a coiled spring made of metal to provide a return force to the frame and the trigger handle. The frame, the nozzle and the delivery arm of the trigger sprayer are molded out of plastic material. As a part of the frame of the trigger sprayer the flexure is located between the upper leg and the lower leg of the frame and is also made of plastic.
The frame, including the trigger handle, the upper leg and lower leg, the flexure and the cap, is made of one piece of plastic. It is essential to have rotational freedom for the trigger handle, while being pressed down. Insufficient rotational freedom would cause significant damage, since the frame would be stretched above the Hook limit. The flexure provides this rotational freedom for the trigger handle. Thus, while pressing down the trigger handle, the plastic material of the frame, especially the flexure, is stressed and because of its plastic memory, it urges the frame, including the trigger handle, back to its home position. The returning force of the flexure is negligible and therefore the patentee suggests that the plastic flexure be replaced by a metal flexure, if necessary.
The major returning force of this trigger sprayer is provided by the metal spring of the pumping mechanism, and the main feature of the flexure is to provide rotational freedom to the trigger handle.
Additionally, a metal ferrule is used to seal the pumping device against the cap of the frame.
The Libit U.S. Pat. No. 4,352,443 discloses a pump dispenser including a sprayhead and a trigger-bulb pump wherein a trigger acts on a bulb to pump liquid into the bulb and then out of the bulb to a nozzle end. The trigger has a flexible flange member with contours that cooperate with the bulb and the sprayhead to form intake and outlet valves and an air breather valve. This patent does not describe the composition or material from which all the parts of the pump dispenser are made but the cross hatching in the drawings indicate that many of the components are made of plastic.
The Pauls et al. U.S. Pat. No. 4,781,311 discloses a multi-function dispenser adjustable to obtain a spray or stream of the material dispensed, either as a long duration discharge of the material or as intermittent discharges corresponding to actuation of a trigger actuator, or as a continuous discharge during actuation of the trigger, depending upon functional design variables. Structure is provided for storing an accumulated amount of material upon repeated operations of the trigger, for subsequent prolonged discharge of the material. The accumulating structure may be bypassed for intermittent discharge of the material as the trigger is operated, or the accumulating structure may function as a holding chamber whereby a continuous discharge of the material may be obtained while the trigger is being operated.
The multi-function dispenser is made mainly out of synthetic material, but incorporates also other materials, e.g. a rubber bladder or a metal valve actuator rod.
The Grogan et al U.S. patent discloses a dispensing pump wherein a trigger is pivotally mounted to a body by, what appears from the cross hatching in FIG'S. 4 and 5 of the drawings, a metal pin. The trigger acts against a resiliently deformable diaphragm which has an encircling flange that forms inlet and outlet valves. This patent does not describe the composition or material from which all the parts of the dispensing pump are made but the cross hatching in the drawings indicate that many of the components are made of plastic.
As will be described in greater detail hereinafter, the trigger sprayer of the present invention differs from the previously proposed trigger actuated sprayers by including in a piston and cylinder type trigger sprayer only synthetic or plastic parts, which enables the trigger sprayer to be recycled easily.